The growing popularity of pools for recreational, therapeutic and domestic use has resulted in the creation of a plurality of types and models, intended to meet the market's large variety of expectations. Among others, the most widely known are the following:                concrete pools, lined with tiles, miniature tiles or vinyl linings;        fiberglass pools, manufactured according to standard dimensions and shapes;        mixed-type pools, with a concrete base (bottom) and walls made of blocks, clay bricks or metallic sheets, usually waterproofed with vinyl lining or fiberglass skin.        
However, constructing pools of the above mentioned types is a relatively complex, slow and expensive process, since, in addition to requiring specialized labor, they have disadvantages inherent to their nature.
In fact, it is known that concrete structures require the manufacture of molds that, once used, are disposed of, resulting in a substantial waste of material.
Fiberglass pools, although not having this shortcoming, require digging a hole in the ground with the proper dimensions, as well as the provision of a concrete support bottom.
Additionally, neither concrete nor fiberglass pools can be moved to another location, nor can they have their dimensions altered, leaving no choice for their owners but to live with the original dimensions forever. For instance, in a pool built for small children, it becomes impossible to increase its depth when these children grow up.
Conventional pools have other shortcomings, such as the need for special techniques to install underwater lighting (which must be planned before the construction begins), as well as the impossibility of altering the number or positions of these lighting fixtures after the construction is finished.
The above-mentioned inconveniences have led to the search for solutions based on modular techniques, in order to result in more accessible costs, as well as to reduce assembly time and to facilitate said assembly work. This trend is exemplified by patent documents U.S. Pat. No. 3,798,857 to Barrera (hereinafter “Barrera”), U.S. Pat. No. 3,820,174 to Rozanski (hereinafter “Rozanski”), U.S. Pat. No. 4,047,340 to Witte et al (hereinafter Witte) and DE 1264031 to Dr. Theodor Kootz (hereinafter “Kootz”).
The inventions described in the above-mentioned documents, however, have shortcomings that limit their usefulness, as discussed below. Barrera discloses a pool whose walls consist of modules made of steel sheets, equipped with coupling means between the vertical edges of adjacent modules, whose assembly results in the pool's side walls, as shown in FIG. 1. Said coupling means comprise rectangular slots into which tabs are inserted, the retention between modules being provided by locking pins. The shapes of these tabs require expensive manufacturing processes. Moreover, as shown in FIG. 1, the pool has to be placed inside a hole dug into the ground.
In addition, the modules of Barrera do not apply to the bottom of the pool, which is made of concrete and requires specialized as well as costly labor, which is also needed to manufacture the concrete blocks that provide support to the walls' anchor beams.
Rozanksi discloses a pool whose walls are made of steel sheet modules, complemented by a three-dimensional lattice structure as shown in FIGS. 2 and 3. The object of this is to provide a supporting structure for the ladder's handrails, as well as supporting a concrete deck or pavement surrounding the edge of the pool. As in the previous example, the bottom of the pool requires specialized labor, which is also necessary to lay the concrete pavement. These operations are time consuming, due to the time needed for the concrete to harden.
Witte discloses a pool with walls made up of modular plate-shaped elements that have, in their vertical edges, grove and tongue joints. The horizontal forces are supported by X-shaped prefabricated elements, as shown in FIGS. 4 and 5. As shown in FIG. 5, a concrete bottom 90 must be provided to support the wall modules 32 as well as the internal edge of the deck 20 that surrounds the pool. The external edges of said deck rests upon one of the arms 50 of the X-shaped elements, whose bottom arm 50d rests on a metallic footing 80 that is secured to the ground or according Witte—a concrete base, not shown in the drawing. Said base is necessary due to the fact that the thrust resulting from the water's pressure upon the walls is also unloaded on this footing. In the subject matter of this patent, the same considerations regarding the delay in the construction time are also applicable.
Kootz teaches a swimming pool having its bottom, as well as its sides, formed of metallic tray-like modules that are bolted together. The pool has two parts with different depths: in the shallower part, the walls are composed of a single row of panels, whereas in the deeper portion, the walls are higher, being formed of two superposed rows of panels. In the bottom of the pool, the tray-like panels are placed with their flanges facing up (i.e., the inside of the pool). This configuration is necessary due to the fact that said panels must be bolted together to form the bottom. However, to attain a uniform bottom surface, the trays must be filled with concrete covered with a fiberglass layer. Therefore, the pool cannot be disassembled, as the bolts which join said bottom panels are be encased in concrete. Moreover, said bottom panels have to be laid on a leveled surface, preferably, one that has been compacted or overlaid with a layer of concrete. Additionally, the horizontal thrust upon the side panels, due to the water pressure, may result in the outward bending of the walls of said deeper portion, mainly along the joints between the upper and lower rows of panels. This sets a limit to the number of panels that can be superposed to increase the height of said side walls and, therefore, the pool's depth.
The above-mentioned examples of the state of the art suffer from serious shortcomings due to the possibility of structural damages due non-uniform resistance from the ground on which the pool lies. Such is particularly the case with the objects of Barrera and Witte.